RANEY-NICKEL CATALYZED HYDROGENATIONS - GAS-LIQUID MASS-TRANSFER IN GAS-INDUCED STIRRED SLURRY REACTORS

Gas-liquid mass transfer in gas induced stirred reactors has been investigated by the method of physical absorption, based on pressure variation. Using two different gas-inducers, liquid composition temperature and height in the reactor, gas pressure and type, solid catalyst type and concentration have been varied in a lab reactor. Without solid phase, the data correlated with the stirrer speed as well as with the energy dissipation rate deduced from torque measurements, which proves the equivalent efficiencies of the two gas-inducers. Very complex and striking effects of small addition of catalyst were observed, depending on the nature of the Raney nickel, pyrophoric or not, and on the liquid phase, stressing the need of measurements with the actual liquid and solid phases. Important reaction rate enhancement could result from a convenient catalyst-solvent system involving catalyst adhesion or shuttling at gas-liquid interfaces.